In recent years, there has been an increased focus on reducing emissions of greenhouse gases generated by burning fossil fuels. One solution for reducing greenhouse gas emissions is developing renewable sources of energy. Particularly, energy derived from the wind has proven to be an environmentally safe and reliable source of energy, which can reduce dependence on fossil fuels.
Energy in wind can be captured by a wind turbine, which is a rotating machine that converts the kinetic energy of the wind into mechanical energy, and the mechanical energy subsequently into electrical power. Common horizontal-axis wind turbines include a tower, a nacelle located at the apex of the tower, and a rotor that is supported in the nacelle by means of a shaft. The shaft couples the rotor either directly or indirectly with a rotor assembly of a generator housed inside the nacelle. A plurality of wind turbines generators may be arranged together in a wind park or wind power plant to generate sufficient energy to support a grid.
In modern high performance wind turbines, it is becoming increasingly important to control the aerodynamic forces in conjunction with the aero-elastic response through active manipulation. Such control may be accomplished not only by aerodynamic means, but also by, for example, controlling the pitch of the blade or the rotational speed of the wind turbine rotor.
Most modern wind turbines are equipped with a wind sensor or sensors on the nacelle capable of detecting the wind speed and direction. Based on the detected wind speed and direction one or more control decisions such as pitching blades, yawing the turbine upwind, etc., may be taken to ensure generation of a desired amount of power, reduction of loads and stresses on wind turbine components, and the like.